Identity documents and document verification.

What a document can and cannot prove

An identity document is a claim, issued by an authority, that a person with a certain name, date of birth and face exists and was known to that authority when the document was issued. Checking one well means answering three separate questions:

• Is the document genuine? Was it really issued by the authority it names, and has it not been altered?
• Is it valid? Is it in date, and has it not been reported lost, stolen or cancelled?
• Does it belong to the person presenting it? Is the person in front of you, or on camera, the person the document describes?

A perfect answer to the first two says nothing about the third. A genuine, valid passport presented by someone other than its owner, even someone who looks very like them, is still fraud. That is why document checks are always paired with a check on the person, such as comparing their face with the document photo.

Most private organisations cannot query lost-and-stolen document databases directly, which are generally for law enforcement. For them, validity usually means checking the expiry date and, where the law allows, confirming the details with the issuing authority.

Documents also have limits. They record what was true when they were issued: an address or name may have changed since. And a genuine document can have been obtained with false information in the first place. Document verification is one strong layer of identity checking, not the whole of it.

Security features

Modern identity documents are designed to be hard to copy and hard to change. They combine several kinds of security feature, so that a forger has to defeat many at once:

• Printing features: fine line patterns such as guilloches, microprinting too small to read without magnification, and inks that are visible only under ultraviolet light.
• Optically variable features, such as holograms and colour-shifting inks, that change appearance as the document is tilted.
• Personalisation features: the holder's details and photo laser-engraved into the card, often with a second, smaller ghost image of the photo, so that replacing the main photo leaves a mismatch.
• Tactile features: raised or engraved areas that can be felt.
• Materials: special papers, watermarks and polycarbonate cards whose layers are fused into one solid body, so they cannot be separated and re-laminated without visible damage.

In person, a trained checker can look, tilt, feel and use an ultraviolet lamp. Remotely, many of these features are hard or impossible to see in a phone photo: ultraviolet features are invisible, and holograms may show only as glare. Remote checks therefore rely more on the image, the layout, the data and, where available, the chip. Knowing which features your process can and cannot actually test is the first step in knowing how much the check is worth.

Reference collections of genuine document designs help checkers know what each document should look like. One public example is PRADO, the European Union's Public Register of Authentic travel and identity Documents Online, currently hosted by the Council of the European Union.

The machine-readable zone and the chip

Passports and many identity cards follow ICAO Document 9303, the International Civil Aviation Organization's standard for machine readable travel documents (currently the eighth edition, 2021, published free in 13 parts).

The machine-readable zone (MRZ) is the block of two or three lines of characters at the bottom of the data page or on the back of a card. It repeats key data, such as document type, issuing country, name, document number, nationality, date of birth, sex and expiry date, in a fixed format that machines can read reliably. It contains check digits calculated from selected fields (the document number, date of birth and expiry date, plus an overall composite digit), so a mistyped or altered number or date usually produces a check digit that does not match. Names are not protected by a check digit. Consistency matters too: the MRZ, the printed details and any chip data should all agree.

A passing check digit does not prove a document genuine. A forger can calculate correct check digits. It is a quick way to catch errors and crude alterations, not a guarantee.

The chip. Electronic passports, and a growing number of identity cards, carry a contactless chip holding the holder's data and photo. The data is digitally signed by the issuing country. A phone with NFC can read the chip once it has unlocked it using details printed on the document (the MRZ or a card access number). Verifying the chip's signature against the issuing country's certificates, a step Document 9303 calls passive authentication, shows the data is genuine and unaltered, provided the verifier holds a trusted copy of that country's certificate. Where the chip supports them, further checks (active authentication or chip authentication) show that the chip itself has not been copied onto another card.

Where a chip is available and can be read and verified, it is usually the strongest single check on a document's authenticity that a remote process can make. Kenya issues ePassports that follow Document 9303, and the Maisha Card introduced in 2023 also carries a chip, though a verifier can rely on a chip only where the issuer makes the means to read and verify it available.

How documents are faked

Document fraud takes several forms, and each defeats a different check:

• Counterfeit: a complete imitation of a genuine document.
• Forged or altered: a genuine document that has been changed, for example a replaced photo or edited date of birth.
• Fraudulently obtained genuine: a real document issued by the authority, but on the basis of false information or a corrupt official. Every feature is genuine; only the identity behind it is false.
• Impostor use: a genuine document, belonging to someone else, used by a person who resembles its owner.
• Stolen blanks: genuine blank documents stolen before personalisation and filled in by criminals.
• Fantasy documents: documents that look official but were never issued by any recognised authority.

Remote onboarding adds digital forms:

• Photographs of screens or printouts instead of the physical document.
• Edited images, where details or photos are changed digitally before upload.
• Template and generated documents: fake documents produced from templates, sometimes built from published specimen images, or with image-generation tools, sometimes in bulk.
• Injected images, supplied to the app directly instead of through the camera.

Useful signals include image evidence of a screen or print, signs of editing, the same document image or number appearing in several applications, and data that does not fit together, such as an issue date before the holder's birth or a document number format the issuer never used.

Designing a document check

A sound document check is layered, proportionate and fair.

• Layer the checks: image quality and capture checks, visual and layout checks, MRZ and data consistency, the chip where available, a check on the person (face comparison and liveness), and, where the law allows, confirmation of the details against an authoritative source such as a national population register.
• Match the depth to the risk: a low-limit account and a high-value relationship do not need the same checks.
• Send uncertain cases to trained people rather than forcing an automatic yes or no, and record the reasons for every rejection.
• Look across applications, not only at each one alone, because organised fraud reuses documents, faces and details.
• Keep only what you need. Copies of identity documents are valuable to fraudsters and are personal data under Kenya's Data Protection Act, 2019. Store them securely, limit who can see them, and keep them only as long as is reasonably necessary for the purpose or as another law, such as anti-money laundering record-keeping rules, requires, then delete or anonymise them (section 39).
• Leave a route for genuine people who fail. Worn documents, poor cameras and people without the usual documents are common. Offer an alternative, such as an in-person check, rather than turning people away.

Finally, test the process with genuine and fraudulent samples, and keep it up to date as documents and fraud techniques change. A document check that nobody has tried to fool is untested.

Your certificate of completion

Enter your name as you want it to appear, then save the certificate as a PDF. In the print window, choose Save as PDF. A certificate is issued once per completion of the course.

Saolix does not record who takes this course, so it cannot verify these certificates. The certificate confirms completion of a free self-paced course and is not an accredited qualification.